The present invention relates to a method of manufacturing a magnetically anisotropic powder material. More specifically, the present invention relates to a method of manufacturing a magnetically anisotropic R-T-B-M powder material which includes an R-T-B-M raw alloy material having a c-axis orientation of a R.sub.2 T.sub.14 B-type intermetallic compound phase for use in manufacturing anisotropic magnets which exhibit superior magnetic properties.
The present invention is also directed to a method of manufacturing anisotropic magnets from the magnetically anisotropic R-T-B-M powder material of the present invention. Magnets produced from such a magnetically anisotropic magnet powder exhibit superior anisotropic properties.
Prior art methods of manufacturing full-density anisotropic magnet comprise the steps of homogenizing an R-T-B-M raw alloy material, which yields an alloy having a recrystallized fine aggregate structure with a R.sub.2 T.sub.14 B-type intermetallic compound phase as the main phase. The alloy consists of R, T and B as its main components and further includes M in an amount of from 0.001 to 5.0 atomic %.
Such prior art methods comprise homogenizing by maintaining a R-T-B-M raw material at a temperature ranging from 600.degree. to 1200.degree. C. in an Ar atmosphere.
Alternatively, the alloy material is heated to a temperature ranging from 500.degree. to 1,000.degree. C. in a hydrogen gas atmosphere or in a mixed gas atmosphere consisting of an inert gas and a hydrogen gas, and maintaining it at this temperature to facilitate hydrogen occlusion. This is then followed by dehydrating the homogenized material by maintaining it in a vacuum or inert gas atmosphere at a temperature ranging from 500.degree. to 1,000.degree. C., then cooling and crushing the homogenized material.
Prior art methods of manufacturing anisotropic bond magnets utilize a bonding technique wherein the R-Fe-B-M magnet powder material is bonded to an organic binder or a metallic binder.
Prior art methods of manufacturing anisotropic full density magnets involve hot-pressing or subjecting to an HIP treatment a R-Fe-B-M magnet powder material at a temperature range of from about 600.degree. to about 900.degree. C. Such prior art methods are disclosed in Japanese Patent Provisional Publication No. 3129,702, Japanese Patent Provisional Publication No. 3-129,703, Japanese Patent Provisional Publication No. 4253,304 and Japanese Patent Provisional Publication No. 4245,403.
However, the R-Fe-B-M magnet powder obtained by any of the conventional manufacturing methods have insufficient magnetic anisotropy when compared to the original magnetic properties of the alloy material.
Additionally, bond and full-density magnets manufactured from such prior art magnet powder materials exhibit inferior magnetic anisotropy.